Granite composition and grain

A 1919 handbook introduced granite through both material composition and visible character. It associated the stone’s usefulness with strength, tone, texture, and polish, then described how accessory minerals informed trade names. Its account is a period overview, not a current engineering specification. (DM PDF p.61)

A varied material

The handbook notes that granites differ in the minerals present and in which accessory mineral predominates. It names biotite, or mica, granites as abundant in the United States. That framing links geological description to a dealer’s practical interest in the stone’s appearance and finish. (DM PDF p.61)

Historical measurements

The same page introduces tables of chemical constituents and physical properties. On the following scanned page, the handbook cautions that strength figures vary with the stock and test conditions and should not be treated as exact. Those qualifications are important: the figures document what the trade was reading at the time, not a modern comparison between stones. (DM PDF pp.61-62; printed p.59 on PDF p.62)

Reading historical data

Use the cited handbook for historical vocabulary and context. It is not a substitute for current material testing, engineering advice, or supplier specifications.

See also

• Regional granite names
• Head-grain polishing claims
• Rock-faced work

Sources

• DM PDF pp.61-62; printed p.59 on PDF p.62.

Source and editorial credit

DM publication record.

This is a modern AI-assisted editorial summary. Named contributors are credited with their specific statements above; unidentified contributors remain unverified. Publication editors are not assumed to have written individual articles. Page references use the private scan; source access, edition and rights limitations are recorded in the linked register.